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arXiv · 1804.03866

Maximum spin polarization in chromium dimer cations as demonstrated by x-ray magnetic circular dichroism spectroscopy

Vicente Zamudio-Bayer·Konstantin Hirsch·Andreas Langenberg·Markus Niemeyer·Marlene Vogel·Arkadiusz Ławicki·Akira Terasaki·J. Tobias Lau·Bernd von Issendorff
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Abstract

X-ray magnetic circular dichroism spectroscopy has been used to characterize the electronic structure and magnetic moment of Cr$_2^+$. Our results indicate that the removal of a single electron from the $4s\sigma_g$ bonding orbital of Cr$_2$ drastically changes the preferred coupling of the $3d$ electronic spins. While the neutral molecule has a zero-spin ground state with a very short bond length, the molecular cation exhibits a ferromagnetically coupled ground state with the highest possible spin of $S=11/2$, and almost twice the bond length of the neutral molecule. This spin configuration can be interpreted as a result of indirect exchange coupling between the $3d$ electrons of the two atoms that is mediated by the single $4s$ electron through a strong intraatomic $3d$-$4s$ exchange interaction. Our finding allows an estimate of the relative energies of two states that are often discussed as ground-state candidates, the ferromagnetically coupled $^{12}\Sigma$ and the low-spin $^2\Sigma$ state.

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Vicente Zamudio-Bayer, Konstantin Hirsch, Andreas Langenberg, Markus Niemeyer, Marlene Vogel, Arkadiusz Ławicki, Akira Terasaki, J. Tobias Lau, Bernd von Issendorff. 2018-04-11. Maximum spin polarization in chromium dimer cations as demonstrated by x-ray magnetic circular dichroism spectroscopy. https://doi.org/10.1002/anie.201411018

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